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Electrical characterization of high performance, liquid gated vertically stacked SiNW-based 3D FET biosensors
Buitrago, Elizabeth; Badia, Monserrat Fernández-Bolaños; Georgiev, Yordan M.; Yu, Ran; Lotty, Olan; Holmes, Justin D.; Nightingale, Adrian M.; Guerin, Höel M.; Ionescu, Adrian M.
A 3D vertically stacked silicon nanowire (SiNW) field effect transistor featuring a high density array of fully depleted channels gated by a backgate and one or two symmetrical platinum side-gates through a liquid has been electrically characterized for their implementation into a robust biosensing system. The structures have also been characterized electrically under vacuum when completely surrounded by a thick oxide layer. When fully suspended, the SiNWs may be surrounded by a conformal high-κ gate dielectric (HfO2) or silicon dioxide. The high density array of nanowires (up to 7 or 8 × 20 SiNWs in the vertical and horizontal direction, respectively) provides for high drive currents (1.3 mA/μm, normalized to an average NW diameter of 30 nm at VSG = 3 V, and Vd = 50 mV, for a standard structure with 7 × 10 NWs stacked) and high chances of biomolecule interaction and detection. The use of silicon on insulator substrates with a low doped device layer significantly reduces leakage currents for excellent Ion/Ioff ratios >106 of particular importance for low power applications. When the nanowires are submerged in a liquid, they feature a gate all around architecture with improved electrostatics that provides steep subthreshold slopes (SS < 75 mV/dec), low drain induced barrier lowering (DIBL < 20 mV/V) and high transconductances (gm > 10 μS) while allowing for the entire surface area of the nanowire to be available for biomolecule sensing. The fabricated devices have small SiNW diameters (down to dNW ∼ 15–30 nm) in order to be fully depleted and provide also high surface to volume ratios for high sensitivities.
Keyword(s): ISFET; Sensor; FinFET; SiNW; GAA; Ion sensitive field effect transistor; Biomolecules; Gate dielectrics; Hafnium oxides; Leakage currents; Nanowires; Sensors; Silicon on insulator technology; Biomolecule interactions; Drain-induced barrier lowering; Electrical characterization; High surface-to-volume ratio; Silicon-on-insulator substrates; Liquids
Publication Date:
Type: Journal article
Peer-Reviewed: Yes
Language(s): English
Institution: University College Cork
Funder(s): Science Foundation Ireland
Citation(s): BUITRAGO, E., BADIA, M. F.-B., GEORGIEV, Y. M., YU, R., LOTTY, O., HOLMES, J. D., NIGHTINGALE, A. M., GUERIN, H. M. & IONESCU, A. M. 2014. Electrical characterization of high performance, liquid gated vertically stacked SiNW-based 3D FET biosensors. Sensors and Actuators B: Chemical, 199, 291-300.
Publisher(s): Elsevier
Alternative Title(s): Electrical characterization of high performance, liquid gated vertically stacked SiNW-based 3D FET for biosensing applications
File Format(s): application/pdf
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First Indexed: 2016-07-13 05:48:01 Last Updated: 2016-10-14 05:53:29